WEIGHTS & VIN PLATES!

The information here is based on a motorhome conversion of a commercial chassis but it holds true for virtually any vehicle.

VIN stands for Vehicle Identification Number.

It's a unique 17 digit number which includes coded information such as Country of Assembly, the Manufacturer, the Body Style and Engine, and the year of build. The last 6 digits are the vehicle's serial number and when all are combined, it's the unique 'fingerprint'. It should be stamped in the chassis but may also be found around the engine block, the driver's door jamb and probably in the boot.

Additionally, it should be stamped on a VIN plate (usually located just under the

bonnet) and the plate will also show various weights.

When a vehicle has been converted or modified (i.e. campervans/motorhomes) the converter will add there own plate or sticker which may modify the weights.

It's vital you understand your vehicles VIN plate. Exceeding ANY ONE of the listed weights is an offence.

What weights are shown? From top to bottom in the example shown is the MAM (Maximum Authorised Mass), GVW (Gross Vehicle Weight) or MGW (Maximum Gross Weight) followed by GTW (Gross Train Weight) or GCW (Gross Combined Weight).

The numbers 1. 2. and 3. are axle weights. 1. is the maximum allowable weight of the front axle. 2. is the maximum allowable weight of a single rear axle. 3. is the maximum allowable weight of a third or 'tag' axle.

Axle weights added together should exceed the GVW which allows for some margin in the way the vehicle is loaded.

What weights are NOT shown? The VIN plate will not show the unladen or kerb weight, the payload, the towing limit or the towbar noseweight.

The unladen or kerb weight should be in the vehicle handbook. However, to be sure, have the vehicle weighed on a weighbridge. The difference between the unladen weight and the MGW is the maximum allowable PAYLOAD.

The towing limit can be calculated by deducting the MGW from the GTW. The resulting figure is assuming that the vehicle is fully laden. In the event that the full payload isn't being used, the balance can be added to the calculated towing limit.

The towbar itself should have a type approval sticker which shows a 'D' value and an 'S' value. The 'S' value quite simply is the maximum allowable noseweight. The 'D' value is rather more complicated and is a calculation based on the GVW and the maimum towing limit. I shall cover this in another blog.

REMEMBER! 1. Do NOT exceed any of the weights on the VIN plate.

2. Check your driving licence categories and limits to ensure you are legal!

Check Noseweight for Stability!

Whatever trailer you tow, stability is all important.

Snaking is not an uncommon problem on high sided trailers such as caravans, or on combinations with a long overhang on the trailer. There are aids that can be used to help control it but getting the noseweight right initially is fundamemtal.

Commercial noseweight gauges are available such as the MP970 Noseweight Indicator Gauge from Maypole. https://www.maypoleltd.com/product/mp970-noseweight-indicator-gauge/.

However, bathroom scales, used correctly, will work equally well!

Using my method, checking the weight of both single and double (or multi) axle trailers is straightforward.

Towball height is critical! Especially on twin or triple axle trailers. On multi axles, If you need to push the coupling downwards on to the towball, the noseweight is NEGATIVE and the unit will be highly unstable. Having to push downwards puts more weight on the trailers front axle and in extreme circumstances it can be overloaded while the rear axle(s) are doing almost nothing. If you need to lift the coupling up to get it onto the ball, noseweight could be excessive and over the allowable limits of the towball, tow-bar and vehicle chassis. The trailer's front axle will be unloaded while the rear is over loaded.

STEP 1. On level ground, locate the trailer onto the towball and lift the jockey wheel clear, if fitted. Towing vehicles vary but with soft suspension, it's possible the ball height could be significantly lower when laden compared with unladen.

STEP 2. Measure the height from the ground to the centre of the towball/coupling head. Record this height when the towball is laden.

STEP 3. Unhitch the trailer and replace the towball with the noseweight guage, set at the prerecorded height.

If using bathroom scales, ensure they are on a flat surface, protect the platen with a sheet of plywood or similar and use a broom handle cut to the required length, allowing for the depth of the scales. Record the noseweight.

STEP 4. If the load needs to be adjusted, REMOVE the noseweight guage, ensure the jockey wheel is down and the handbrake is securely applied. With a car on a transporter, just a few inches backwards or forwards will make a big difference to the noseweight. The ideal weight is likely to be NOT LESS than 50kg, aiming for around 7% of the gross trailer weight. (1 tonne gross = 70kgs noseweight).

STEP 5. With a car on a transporter, once the desired weight is achieved, be sure to fix chocks to the deck, in front of the front wheels. On subsequent uses, you should then be able to just drive straight up to them and be right first time. ENSURE the vehicle is securely strapped down!

DO NOT exceed the maximum allowable noseweight of the vehicle chassis (should be shown in the handbook) or of the coupling, the towball or the towbar. Noseweight on type approval plates is shown as the 'S' value in kgs.

My Life in the Towing & Trailer Industry.

My Towing History…

I first became a part of the ‘Towing Industry’ in 1975 when I was the PA to the MD of group of companies in the Leisure Trade. We did wholesale and retail of camping and caravanning equipment and caravans themselves. Additionally, one of the companies was, at that time, the most prolific manufacturer of trailers in the U.K. supplying the mail order companies such as Freemans and Grattans with over 300 per week. As the P.A., I filled in wherever I was needed, including in the trailer company where I learned a lot! 5 years later I had my own business, retailing trailer tents, trailers and towing equipment. I started a hire fleet and soon discovered the off the peg trailers were far from adequate. From then on, I designed and built my own, cat 01 and 02 trailers, up to 3,500kgs. These included car transporters, horse trailers, motorcycle trailers, one off bespoke trailers, car dollies, etc, etc. I had some experience in design and technology and had studied physics & chemistry to ONC level. I had studied metallurgy and welding technology and was a qualified welder.

Quality was at the forefront of everything we did, from day one. Alongside my own business, after joining the NTTA, I was appointed a council member and director. I was a part of the steering committee that eventually founded the NTTA’s QS scheme. Following my work there, my own business became the first in the U.K. to be ‘QS Approved’ and we were also the first to introduce ‘Lifetime Warranties on our towbar fittings. After attending courses run at Bolton College, I established the first dedicated training centre to provide training to the industry (on behalf of the NTTA) on Trailer Maintenance as well as Towbar Fitting and Electrics. This was at a time when canbus systems were first becoming mainstream. Some of the modules I delivered were on trailer and towing legislation.

Everything done on the courses was aimed at raising standards throughout the industry as a whole. Quality was the keyword. As an example, Practical tests on the courses showed that 12volt fridge and charging supplies via the 12S system were wholly inadequate. Voltage checking, UNDER LOAD, was introduced as a result on all of our towbar fittings. PUBLICATIONS. Over 20 years ago I wrote an article ‘Towing behind a Motorhome—-What you should Know. The legislation quoted there is still relevant today and it can be seen at https://www.ukcampsite.co.uk/articles/view.asp?id=18 After tests on the courses, I devised a solution for 12S Pin Burnout… the resulting article is here.. https://www.towitall.co.uk/faq/ Additionally, I was a Photographic and journalistic contributor to the Haynes manual , The Trailer Manual, ISBN 978-1-84-425212-1.

I have been aware of a major inconsistency in trailer & towing legislation and regulation for over 30 years. Having now retired, I can now direct some effort towards trying to have that addressed. It concerns the total lack of control/regulation and effective legislation regarding A-Frame towing of vehicles. i.e. A-Framing/Towed Vehicles/Towed Cars/TOADS.